$green = #02a774
$yellow = #F5A100
$bc = #e4e4e4
// 一像素下边框
bottom-border-1px($color)
  position: relative
  border: none
  &:after
    content: ''
    position: absolute
    left: 0
    bottom: 0
    width: 100%
    height: 1px
    background-color: $color
    transform: scaleY(0.5)
// 一像素上边框
top-border-1px($color)
  position: relative
  &::before
    content: ''
    position: absolute
    z-index: 200
    left: 0
    top: 0
    width: 100%
    height: 1px
    background-color: $color
// 根据像素比缩放1px像素边框
@media only screen and (-webkit-device-pixel-ratio: 2)
  .border-1px
    &::before
      transform: scaleY(0.5)
@media only screen and (-webkit-device-pixel-ratio: 3)
  .border-1px
    &::before
      transform: scaleY(0.333333)
// 根据像素比来使用 2x图 3x图
bg-image($url)
  background-image: url($url + '@2x.png')
  @media (-webkit-min-device-pixel-ratio: 3), (min-device-pixel-ratio: 3)
    background-image: url($url + '@3x.png')
// 清除浮动
clearFix()
  *zoom: 1
  &::after
    content: ''
    display: block
    clear: both